After the reported birth of CRISPRed babies in China, experts want to take time to consider the scientific, social, ethical, and philosophical consequences of editing heritable human DNA.

Mar 13, 2019

There should be a global moratorium on editing heritable DNA from humans, scientists and bioethicists from seven countries write today (March 13) in a Nature commentary. The US National Academy of Medicine, the US National Academy of Science, the UK Royal Society, London, and the National Institutes of Health support the call for prohibiting such editing until an international framework on the technique’s use can be established.

“We all believe that we shouldn’t be going forward,” Eric Lander, director of the Broad Institute of Harvard and MIT and coauthor of the commentary, tells NPR. “And starting off by saying we should have a moratorium brings an important clarity to the thing.”

Editing heritable DNA, or germline editing, involves using CRISPR-Cas9 or other methods to tweak the genetic code of sperm, eggs, or embryos with the goal being to make genetically modified children. The proposed moratorium does not include germline editing research on embryos that will not be transferred to a human’s uterus or editing of somatic cells to treat disease. It’s only aimed at stalling researchers from making edits that could be passed down generation after generation.

“This is a crucial moment in the history of science: a new technology offers the potential to rewrite the script of human life. We think that human gene editing for reproductive purposes carries very serious consequences—social, ethical, philosophical and theological,” Carrie Wolinetz, associate director for science policy at the National Institutes of Health (NIH) and Francis Collins, director of the NIH, write in a Nature correspondence supporting the global moratorium. “Such great consequences require deep reflection.”

The proposal comes in response to Chinese biophysicist He Jiankui having reportedly edited the embryos of two babies to prevent them from contracting HIV in the future. The intervention aimed to inactivate the CCR5 gene, which encodes a receptor that HIV uses to enter cells.

As Lander and colleagues note in their commentary, that tweak could cause other consequences, such as increasing the risk of complications or death from West Nile virus, influenza, and other viral infections.

Perhaps more concerning is the “wide agreement in the scientific community that, for clinical germline editing, the risk of failing to make the desired change or of introducing unintended mutations (off-target effects) is still unacceptably high,” the authors note. It’s therefore not really clear how germline editing could affect humans.

“Attempting to reshape the species on the basis of our current state of knowledge would be hubris,” Wolinetz and Collins note.

As a result of He’s attempts at germline editing (a second pregnancy with a CRISPR baby has been reported), the Chinese government tightened regulations on experiments using gene editing, gene transfer, or gene regulation. He’s work violated the country’s ban on using gene-manipulated embryos for reproductive purposes. About 30 nations already have legislation that in some way bans germline editing, according to Lander and his colleagues. Their call for a moratorium would allow time for researchers and regulatory agencies around the world to develop an international framework that might be used to assess the application of germline editing. The framework might, for example, call for a five-year moratorium and then afterward a country could consider germline editing endeavors if, first, it allowed time for public notice and international conversation on using the technique, second, carefully and transparently evaluated the “technical, scientific and medical considerations, and the societal, ethical and moral issues,” to justify using the technique, and third, established “broad societal consensus in the nation” on using the technique and on “the appropriateness of the proposed application,” according to Lander and his colleagues. “The governance model we present would intentionally leave room for nations to take differing approaches,” they write.

“What we’re talking about here is one of the most fundamental moments of decision about the application of science to something of enormous societal consequence,” Collins tells The Washington Post. “Are we going to cross the line toward redesigning ourselves?”